The present invention is directed generally to image guided surgery, and more particularly, to systems and methods for using one or more fluoroscopic X-ray images to assist in instiuent navigation during surgery.
Modern diagnostic medicine has benefitted significantly from radiology, which is the use of radiation, such as x-rays, to generate images of internal body structures. In general, to create an x-ray image, x-ray beams are passed through the body and absorbed, in varying amounts, by tissues in the body. An x-ray image is created based on the relative differences in the transmitted x-ray intensities.
Techniques are known through which x-ray images are used to locate the real-time position of surgical instruments in the patient anatomy represented by the x-ray image without requiring x-rays to be continually taken. In one such system, as disclosed in U.S. Pat. No. 5,772,594 to Barrick, light emitting diodes (LEDs) are placed on a C-arm fluoroscope x-ray imager, on drill, and on a reference bar positioned on the bone to be studied. A three-dimensional optical digitizer senses the position of the LEDs, and hence the position of the drill, the C-arm fluoroscope, and the object bone. Based on this information, the real-time position of the drill in anatomy represented by the x-ray image is determined, and a corresponding representation of the drill in the x-ray image is displayed. This allows the surgeon to continually observe the progress of the surgery without necessitating additional x-ray images.
Surgical navigational guidance, as discussed above, can provide a tool for helping the physician perform surgery. It is an object ofthe present invention to provide several enhancements to traditional surgical navigational guidance techniques.
Objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
One aspect of the present invention is directed to an x-ray imaging device comprising a plurality of elements. In particular, the x-ray imaging device includes an x-ray source for generating cycles of x-ray radiation corresponding to an image acquisition cycle; an x-ray receiving section positioned so that x-rays emanating from the x-ray source enter the x-ray receiving section, the x-ray receiving section generating an image representing intensities of the x-rays entering the x-ray receiving section. Additionally, a computer is coupled to the x-ray receiving section and radiation sensors are located in a path of the x-rays emitted from the x-ray source. The radiation sensors detect the beginning and end of a radiation cycle and transmit the detected beginning and end of the radiation cycle to the computer.
Another imaging device consistent with the present invention includes a rotatable (C-arm support having first and second ends. The first end includes an x-ray source for initiating an imaging cycle and the second end includes an x-ray receiving section positioned so that x-rays emanating from the x-ray source enter the x-ray receiving section. The x-ray receiving section generates an image representing the intensities of the x-rays entering the x-ray receiving section. Further, a calibration and tracking target is included and a tracking sensor detects the position, in three-dimensional space, of the calibration and tracking target; and a computer is couples to the x-ray receiving section and the tracking sensor. The computer detects motion of the C-arm based on changes in the position detected by the tracking sensor.
Another aspect consistent with the present invention is directed to a surgical instrument navigation system. The system comprises a computer processor; a tracking sensor for sensing three-dimensional position information of a surgical instrument and transmitting the position information to the computer processor; a memory coupled to the computer processor, the memory including computer instructions that when executed by the computer processor cause the processor to generate an icon representing the surgical instrument and to overlay the icon on a pre-acquired x-ray image, the icon of the surgical instrument representing the real-time position of the surgical instrument projected into the pre-acquired x-ray image and the icon being generated as first representation when the surgical instrument is positioned such that it is substantially viewable in the plane of the pre-acquired image and the icon being generated as a second representation when the surgical instrument is positioned such that it is substantially perpendicular to the plane of the pre-acquired image. Finally, a display is coupled to the processor for displaying the generate icon superimposed on the pre-acquired image.
Yet another system consistent with the present invention comprises a computer processor and a tracking sensor for sensing three-dimensional position information of a surgical instrument and transmitting the position information to the computer processor. A memory is coupled to the computer processor, the memory including computer instructions that when executed by the computer processor cause the processor to generate an icon representing the surgical instrument positioned in a pre-acquired image of a patient""s anatomy, the icon of the surgical instrument including a first portion corresponding to an actual position of the surgical instrument and a second portion corresponding to a projection of the surgical instrument along a line given by a current trajectory of the surgical instrument. A display is coupled to the processor for displaying the generated icon superimposed on the pre-acquired image.
Still further, another surgical instrument navigation system consistent with the present invention comprises a rotatable C-arm including an x-ray source and an x-ray receiving section for acquiring x-ray images of a patient, the C-arm being rotatable about one of a plurality of mechanical axes. A computer processor is coupled to the rotatable C-arm and a memory is coupled to the computer processor. The memory stores the x-ray images acquired by the rotatable C-arm and computer instructions that when executed by the computer processor cause the computer processor to generate a line representing a projection of a plane parallel to one of the plurality of the mechanical axes of the C-arm into the x-ray image, the line enabling visual alignment of the one of the plurality of mechanical axes of the C-arm with an axis relating complimentary image views. A display is coupled to the processor for displaying the generated line superimposed on the x-ray image.
Yet another system consistent with the present invention is for defining a surgical plan and comprises an x-ray imaging device; a surgical instrument; a tracking sensor for detecting the position, in three-dimensional space, of the surgical instrument; a computer processor or in communication with the tracking sensor for defining a point in a virtual x-ray imaging path is the three-dimensional location of the surgical instrument, the point being outside of a true x-ray imaging path of the x-ray imaging device, the computer processor translating position of the surgical instrument within the virtual x-ray imaging path to a corresponding position in the true x-ray imaging path; and a display coupled to the processor for displaying a pre-acquired x-ray image overlaid with an iconic representation of the surgical instrument, the position of the iconic representation of the surgical instrument in the pre-acquired x-ray image corresponding to the translated position of the surgical instrument.
Yet another system consistent with the present invention for defining a surgical plan comprises a combination of elements. The elements include an x-ray imaging device; a surgical instrument; a tracking sensor for detecting the position, in three-dimensional space, of the surgical instrument; a computer processor in communication with the tracking sensor for calculating a projection of the trajectory of the surgical instrument a distance ahead of the actual location of the surgical instrument; and a display coupled to the processor for displaying a pre-acquired x-ray image overlaid with an iconic representation of the surgical instrument and the calculated projection of the trajectory of the surgical instrument.
Yet another system consistent with the present invention is for aligning a first bone segment with a second bone segment in a patient. The system comprises a first tracking marker attached to the first bone segment and a second tracking marker attached to the second bone segment. A tracking sensor detects the relative position, in three-dimensional space, of the first and second tracking markers. A computer delineates boundaries of images of the first and second bone segments in a pre-acquired x-ray image and when the second bone segment is moved in the patient, the computer correspondingly moves the delineated boundary of the second bone segment in the x-ray image. A display is coupled to the computer and displays the pre-acquired x-ray image overlaid with representations of the delineated boundaries of the first and second bone segments.
Yet another system consistent with the present invention is directed to a system for placing a surgical implant into a patient. The system comprises a computer processor; means for entering dimensions of the implant; a tracking sensor for sensing three-dimensional position information of a surgical instrument on which the surgical implant is attached, the tracking sensor transmitting the position information to the computer processor; and a memory coupled to the computer processor, the memory including computer instructions that when executed by the computer processor cause the processor to generate an icon representing the surgical instrument and the attached surgical implant, and to overlay the icon on a pre-acquired two-dimensional x-ray image, the icon of the surgical instrument representing the real-time position of the surgical instrument relative to the pre-acquired two-dimensional x-ray image.
In addition to the above mention devices and systems, the concepts of the present invention may be practiced as a number of related methods.
An additional method consistent with the present invention is a method of acquiring a two-dimensional x-ray image of patient anatomy from a desired view direction. The method comprises generating the two-dimensional image using an x-ray imager; specifying a view direction in a three-dimensional image representing the patient anatomy; generating a two-dimensional digitally reconstructed radiograph (DRR) image based on the three-dimensional image and the specified view direction; and determining that the two-dimensional x-ray image corresponds to the desired view direction by matching the DRR image to the x-ray image.
Another method consistent with the present invention is a method of calculating angle between a surgical instrument and a plane selected in an x-ray image. The method comprises a number of steps, including: defining at least two points in the x-ray image; defining a plane passing through the x-ray image as the plane including the two points and linear projections of the two points as dictated by a calibration transformation used to calibrate the x-ray image for its particular imaging device; sensing a position of the surgical instrument in three-dimensional space; and calculating the angle between intersection of a projection of the surgical instrument in three-dimensional space and the plane.
Yet another method consistent with the present invention is a method for aligning a fluoroscopic imager with a view direction of the medial axis of a patient""s pedicle. The method comprises displaying a three-dimensional image of an axial cross-section of vertebra ofthe patient; extracting an angle from the three-dimensional image corresponding to the angle separating an anterior/posterior axis and the medial axis of the pedicle; aligning the fluoroscopic imager with a long axis of the patient; and rotating the fluoroscopic imager about the long axis of the patient through the measured angle.